Research Interests

Current

Life experiences are transient, yet they often leave lasting footprints on the mind and brain. Two people can live through nearly identical moments and come out changed in entirely different ways. Why are you and I different? How can we define “different” and how can it be quantified reliably? These two questions are where my current interest begins.

a. Why do individuals interpret and weigh the same experience so differently, to the point where one person forgets it and another carries it for years?

What we perceive is not a direct copy of the world. It is already a reconstruction built from whatever the senses picked up. Processes such as attention allocation, executive control, and mind wandering interact to shape which aspects of incoming information and internally generated thought are amplified or fade from consciousness. Some impressions fade quickly, while others persist and shape how later information is processed. Over time, these experiences may reshape an individual’s expectations and priors (biases). I want to understand why individuals differ in how these processes operate, how these differences are reflected in large-scale brain organization, and how they relate to emotional and behavioral patterns.

b. How can we better represent the brain to capture individual differences in biologically interpretable ways?

Studying during my cross-atlas connectome transformation project, I questioned how our choices in processing and summarizing brain data shape what we can learn about individuals.

I want to understand which aspects of brain organization different representations capture, how reliably they reflect patterns shared across individuals and those specific to each person, and what these patterns reveal about cognitive processes. By examining both shared and individual-specific features, I hope to better understand the neural basis of cognition and why people differ in how they process and respond to experience.

Brief descriptions of my current projects: Click ‘Current’ section of the Project menu.

Post-master's (early)

a. What underlying components are shared across symptoms and disorders that we usually describe separately?

My interest in this question grew from studying symptom heterogeneity in Parkinson’s disease. I began to question how well clinical scores and diagnostic categories capture the processes underlying diverse neuropsychiatric symptoms. Could symptoms described separately share underlying neural processes, while similar clinical presentations arise through different pathways? I became interested in a transdiagnostic approach, using multiple behavioral and clinical measures to explore latent phenotypic dimensions and their relationships with brain network organization.

b. How might differences in the flexibility of brain network states contribute to individual vulnerability?

I was interested in how brain networks respond to changing demands, and why some individuals might become more likely to remain in patterns associated with persistent emotional or behavioral difficulties. In particular, I wanted to explore how prior experiences and incoming stimuli influence transitions between states, and whether these processes could help explain differences in vulnerability across individuals. Connecting these dynamics with phenotypic dimensions was a way to ask which processes might be relevant targets for more personalized intervention.

Second half of the master's program

My research began to take a new direction toward human neuroimaging and network-level approaches. It felt like entering an entirely new world. I didn’t even know how to open a raw T1 file at first. Everything felt foreign and overly abstract. But as I learned and practiced, I realized that what initially felt abstract was simply a different way to describe the same brain from a network/system level. It was interesting to see how distal brain regions synchronize and collectively generate human behavior as an output. Working with human MRI felt closer to real life. Instaed of focusing on a single circuit, I learned to analyze structural networks and closely followed functional analyses from non-invasive human MRI data.

Detailed information about the Parkinson’s disease project with Yonsei Severance Hospital: Click here

How would the individuals behave, think or feel? What would it mean to live with reduced drive or emotional flatness?
And how could those phenotype originate from the brain's architecture?

While working on this project, I began to think deeply about disease complexity and individual heterogeneity. Patient with the same diagnosis could differ significantly in their symptoms and experiences. When I saw columns labeled ‘apathy’ or ‘motivation’ in the dataset (represented as numerical scores), I found it difficult to envision what those numbers actulally represented in an actual human being. Even after reading the questionnaires that was used to derive those scores, I kept wondering what these humans with that score/lables felt like from the inside. That gap between quantified measures and realities became one of the most interesting and unresolved questions for me.

First half of the master's program

In the early part of my master’s program, I was interested in how how the brain distributes energy with precise spatiotemporal coordination. Neurons fire within milliseconds, while vessels adjust over seconds, yet the resulting hemodynamic signal remains coherent across space and time.

How is such temporal precision and region specific coordination maintained in the neurovascular system?
What happens when the mechanical condition of this system begin to fail?

These questions led me to view neurovascular coupling as a dynamic control problem embedded in a hierarchical vascular network. I learned that the hierarchical organization of the brain vessel especially interesting. Vessels close to proximal branches (or small-order branches) are surrounded by smooth muscle cells with active contractility, but as vessels bifurcate into smaller perforating branches that penetrate deeper into the parenchyma, they are no longer wrapped by smooth muscle cells but by less contractile pericytes and even endothelial cells. This graudal loss of contractility makes deeper vessels respond more paassively. Then how does a neuronal response occurring deep in the tissue communicate upstream to secure the needed blood supply?

Before tackling these big questions, I wanted to start by examining one aspect of the system that mechanical properties of vessels being the boundary conditions for neurovascular coupling. I focused on how mechanical stress (originating from arterial stiffness) could distort the fine balance between neuronal demand and vascular response, even when pathology didn’t originate in the brain. Although I had to discontinue this work after developing severe mouse allergies, this experience was a turning point for me to shift toward network neuroscience.

For early stage ideas of that time: you can take a look here.

Undergraduate years

I majored biology, studying fundamental disciplines such as biochem, genetics, molecular, cellular, and developmental biology. My first exposure to neuroscience came during a short summer session at UC Berkeley, where I found how differently the brain could be studied compared to the biology I have known.

Later, during a fully funded exchange semester, returning at Berkeley, I took Genetic Factors of Neuropsychology, and this course changed how I thought about science. Until then, I had viewed “intervention” only through pharmacological means. But learning about the transition from DSM-IV to DSM-5 and how redefining autism as a spectrum could expand access to care and insurance coverage, was a eureka moment. I realized that research doesn’t need to end with a prescription to have an impact. Sometimes, understanding a disorder more accurately and carefully measuring its risk factors could directly improve quality of lives. That was the moment I began to see neuroscience not just as molecular mechanisms of the brain, but as a way to connect scientific understanding to real human outcomes.

At that time, I was obsessed with the idea:

What makes something truly interventible? Are there modifiable and systmic factors that can indirectly have an impact on brain health in broad populations?

Returning to Korea, I began my first full-time internship with this question in mind. For detailed project description: click here

Through this project, I began to study brain vasculature and realized how dynamic it is. I learned that blood flow can contribute to the clearance system (such as glympathic pathway). And the blood flow are altered by neurovascular coupling and pathological proteins. Growing interest in coordination between neural activity and local blood supply drove me to apply master program.